Anatomy & Physiology Exam 2 Study Guide Flashcards
Terms in this set (30)
The three types are skeletal muscle, cardiac muscle, and smooth muscle. Skeletal muscles are voluntary and attached to bones.
Produce movement, maintain posture, support soft tissues, guard entrances/exits, and maintain body temperature.
Each muscle fiber is surrounded by endomysium, bundles by perimysium, and the entire muscle by epimysium. Tendons or aponeuroses connect muscles to bones.
Sarcomeres are functional units with thin (actin) and thick (myosin) filaments. Contraction occurs by thin filaments sliding past thick filaments, shortening the sarcomere.
Myosin heads bind to active sites on actin, pivot to pull filaments, then detach and reset. Tropomyosin and troponin regulate access to active sites.
Neurons release acetylcholine (ACh) at the synaptic cleft, triggering an action potential in the muscle fiber's sarcolemma, leading to calcium release and contraction.
A twitch is a single contraction-relaxation cycle. Repeated stimuli before relaxation cause summation, leading to incomplete or complete tetanus.
ATP powers contraction. Creatine phosphate regenerates ATP quickly. Aerobic metabolism provides most ATP at rest; glycolysis supports peak activity anaerobically.
Fatigue results from pH drop due to hydrogen ion buildup, energy depletion, or other factors preventing contraction.
Fast fibers contract quickly, have large glycogen stores, and fatigue rapidly. Slow fibers contract slowly, have many mitochondria and myoglobin, and resist fatigue.
Smaller cells with single nucleus, intercalated discs, automaticity, longer contractions, and inability to undergo tetanus.
Nonstriated, involuntary, can contract over a wide range of lengths, often lacks direct motor neuron control.
Central nervous system (CNS): brain and spinal cord. Peripheral nervous system (PNS): all nervous tissue outside CNS.
Afferent division brings sensory info to CNS; efferent division carries motor commands. Efferent includes somatic (voluntary) and autonomic (involuntary) systems.
Sensory neurons (afferent), motor neurons (efferent), and interneurons (association neurons) that connect sensory and motor neurons.
Support neurons by maintaining environment, myelinating axons, acting as phagocytes, and producing cerebrospinal fluid.
Maintained by sodium-potassium pump balancing sodium ion gain and potassium ion loss, creating a polarized membrane.
Depolarization to threshold, opening of voltage-gated sodium channels, repolarization by potassium channels, and return to resting state.
Saltatory propagation occurs in myelinated axons, jumping between nodes of Ranvier; continuous propagation occurs along unmyelinated membranes.
Neurons communicate at synapses via neurotransmitters like acetylcholine, which is broken down by acetylcholinesterase to end the signal.
Dura mater (outer), arachnoid (middle), and pia mater (inner) protect and support the brain and spinal cord.
Contains gray matter (neuron cell bodies) surrounded by white matter (myelinated axons), with 31 pairs of spinal nerves.
Cerebrum: conscious thought and motor control; diencephalon: relay and integration; brainstem: autonomic control; cerebellum: coordination and posture.
Sympathetic division (fight or flight) arises from thoracic/lumbar spinal segments; parasympathetic division (rest and digest) from brainstem and sacral segments.
Nociceptors (pain), thermoreceptors (temperature), mechanoreceptors (touch, pressure), baroreceptors (pressure changes), and proprioceptors (body position).
Modified neurons in olfactory epithelium that detect chemical stimuli dissolved in mucus, connected to limbic and hypothalamic areas.
Taste buds contain gustatory epithelial cells with taste hairs that detect sweet, salty, sour, bitter, umami, and water tastes.
Fibrous layer (sclera, cornea), vascular layer (iris, ciliary body, choroid), and inner layer (retina with rods and cones).
Rods detect light intensity; cones detect color. Visual pigments absorb light and alter neurotransmitter release to bipolar cells.
Vestibule and semicircular canals detect equilibrium; cochlea detects sound. Hair cells with stereocilia transduce mechanical stimuli.